Antiseptic preparation of patients for surgery conventionally includes a 3-10 minute scrubbing of the affected area with a soap solution followed by the application of a water-soluble antiseptic paint solution. These solutions are generally applied with saturated sponges that are attached to a blade or held with forceps. The sponges are saturated by soaking in open pans of solution. Numerous devices have been developed in an attempt to prevent the dripping of solution associated with the original technique. Another goal was to reduce the time required for application of the antiseptic solution.
The most important problem associated with prior art devices developed to apply surgical prep solutions is the lack of control of the delivery of the fluid to the sponge in a manner that will prevent dripping. Additional problems encountered with such devices include manufacturing complexity, reliability of rupturable joints and inappropriate geometries.
U.S. Patent Nos. 4,415,288; 4,507,111; and 4,498,796 describe a device that includes a liquid-containing rupturable cylindrical cartridge which is slidable within a tubular handle having one or two hollow within a tubular handle having one or two No. 4,497,796, the spikes communicate to recesses bored or burned into the interior of the sponge to facilitate free flow and even distribution of the fluid. In order for fluid to flow by gravity from this device, air must be entrained into the cartridge through the sponge and at least one hollow spike. For the following two reasons, this is not a reliable and predictable means to control the rate of delivery of fluid to the sponge. First, as the sponge becomes wet its air permeability decreases thereby restricting the entrainment of air. Second, hollow tubes with sufficiently small inside diameters to effectively meter the fluid flow rate to prevent dripping tend to "air-lock" due to the surface tension of the liquid. An additional disadvantage of the design of this device is the recesses in the sponge. These recesses are an attempt to improve the predictability of air entrainment and fluid distribution, but add to the manufacturing costs.
The device described in U.S. Pat. No. 3,847,151 includes a sponge mounted on a nozzle extending from a hollow handle which contains an antiseptic solution. The solution is dispensed into the sponge when a rupturable joint in the nozzle is broken and external pressure is applied to the flexible handle. The problems associated with the design of this device include the unreliability of the rupturable joint and the lack of control of the fluid delivery into the sponge. Inherent mass production variability makes the fabrication of a reliable rupturable joint based on stress concentration difficult. After the nozzle is opened, it is very difficult, in practice, to deliver precisely the correct volume of fluid to saturate the sponge without dripping. In addition, as the sponge is wetted by the fluid, its ability to entrain air is diminished.
U.S. Pat. No. 4,148,318 describes a device that includes an antiseptic solution contained in an integral reservoir with a frangible cover. Spikes affixed to a recess in the sponge pierce the cover to release the solution. The disadvantage of this device and other devices that include liquid-containing ampoules, such as those described in U.S. Pat. Nos. 3,891,331 and 4,183,684, is the absence of a means to control the delivery of fluid to the sponge. The absence of a means to control the fluid flow rate to the sponge limits the volume of solution that can be delivered without dripping.
U.S. Pat. No. 4,342,522 describes a roll-on dispenser which includes a porous open-cell foam membrane deformable by an applicator ball to regulate the dispensation of controlled amounts of powders. The amount of material dispensed is dependent upon the porosity of the membrane and the porosity of the membrane is dependent upon the degree of its deformation by the ball upon operation of the dispenser.